Sodium hydroxide in plastic bottles

[nickykinz]

I had heard that NaOH solutions should be stored in plastic bottles as over time it reacts with the glass and I have transferred all my NaOH. I hadn't really thought about the other hydroxides though. Should I also transfer the potassium and calcium hydroxide? Are there any other solutions that should be stored in plastic?

[Labbie]

Where did you hear that NaOH solutions should be stored in plastic bottles? OUr CSIS tells us to store them in amble coloured glass bottles with a rubber stopper. Mine are in amble glass with just caps, have been fine for over 15 years now. THat is a corrosive solutions, and some plastics would go brittle after a while. Some plastics have a diamond shape on the bottom with a number, make sure it is a number for corrosives, I am so sorry I do not know the correct number on plastic bottles for corrosives. BUt perhaps Rob does.

[dime]

Yeah, plastic bottles do get brittle over time. It may be due to light as much as contents. All 1 and 2 litre containers of solutions I have made up are in plastic bottles and have been forever. But occassionally I gently squeeze the bottles at the top to see if they have gone brittle. I did this after a bottle of NaOH solution broke over the Head Teacher's clothes a long time ago.

[Krysia Lee]

If its stored in a glass bottle over time soidum silicate forms. For our sorts of pracs the amount of Si aren't deterimental to our results. You do have to have a plastic top not a glass stopper as the glass will freeze shut. Having said that I store mine in plastic bottles.

[nickykinz]

I heard it on our Qld labbies discussion list a while ago and it has been mentioned again recently. Sounds like it isn't as big a deal as I thought. Using glass stoppers in glass bottles is a definite no no though. I'll keep an eye on the brittleness of my bottles!